Investment Securities Available-for-Sale (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Losses recognized in earnings for trust preferred securities held
Beginning balance	$ 351	$ 10,674
Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized		171
Ending balance	351	10,845
Trust preferred securities
Losses recognized in earnings for trust preferred securities held
Beginning balance	351	10,674
Reduction for debt securities for which other-than-temporary impairment has been previously recognized and there is no related other comprehensive income	0	0
Credit losses on debt securities for which other-than-temporary impairment has not been previously recognized	0	0
Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized	0	171
Sale of debt securities	0	0
Ending balance	$ 351	$ 10,845